[PATCH v2] powerpc: allow opting out of WATCHDOG_RESET() from timer interrupt

Wolfgang Denk wd at denx.de
Thu Mar 19 10:10:11 CET 2020

Dear Rasmus Villemoes,

In message <20200318151651.2510-1-rasmus.villemoes at prevas.dk> you wrote:
> When using CONFIG_(SPL_)WDT, the watchdog_reset function is a lot more
> complicated than just poking a few SOC-specific registers - it
> involves accessing all kinds of global data, and if the interrupt
> happens at the wrong time (say, in the middle of an WATCHDOG_RESET()
> call from ordinary code), that can end up corrupting said global data.
> Also, having WATCHDOG_RESET() called automatically from the timer
> interrupt runs counter to the idea of a watchdog device - if the board
> runs into an infinite loops with interrupts still enabled, the
> watchdog will never fire.
> Allow the board to opt out of this behaviour by setting
> CONFIG_SYS_WATCHDOG_FREQ to 0 - as that setting is currently
> nonsensical, it cannot affect any existing boards.
> Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>

If such a change gets implemented, it should at least be made
consistently, i. e. not only in arch/powerpc/lib/interrupts.c but
also in the timer_interrupt() handler in drivers/timer/mpc83xx_timer.c
and in dtimer_interrupt() in arch/m68k/lib/time.c and wherever else
similar code may exist.

Only changing one plase is not a good idea.

And please add some documentation also to the README.


Best regards,

Wolfgang Denk

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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